1. Field of the Invention
This invention relates generally to the field of data communication. More particularly, this invention relates to transmission of high speed digital data over switched digital voice networks.
2. Background of the Invention
Switched digital networks are becoming increasingly prevalent and are commonly used for voice transmission. As these networks become more and more common, there is a substantial likelihood that a voice call between two geographical locations will be digital from one end to the other. Unfortunately, present dial-up data communication equipment does not take advantage of this fact.
Dial-up data communication normally uses a modem to convert digital data to analog form for transmission. The analog information is then converted back to digital at the receiving end. In this scenario, data transmission rates are currently limited to approximately 19.2 Kbps (assuming no data compression). However, if an end-to-end digital connection is made, up to 56 Kbps (currently) of digital bandwidth is used to carry this information using PCM (Pulse Coded Modulation). Thus, the available bandwidth is inefficiently used. The present invention provides a mechanism for utilizing this available bandwidth for data transmission.